According to Pokémon Go Hub, several players have spotted “test raids” taking place while searching for raids to participate in. They’re difficult to spot because they’re only available for a limited period of time. Plus, even if you do spot one, you can’t actually do it because they’re hosted on employee-only Niantic servers. You basically have to be in the right place at the right time, but if you are, it’s hard to miss the giant “Test” placeholder text for them that appears in the app’s Nearby tab.

One Silph Road member named flipdrago managed to take a screencap of a tier five raid happening in the Disneyland area. Another user shifted the contrast way up, so you can clearly see the tier five ranking:

It looks supremely ugly, but with the contrast cranked up you can see the five Rhydon heads under the “Test” header that seem to indicate tier five raids are on the way.IamJacksFutureBeard/Imgur

Another user, Scooby1222, captured a screenshot of a test raid two weeks ago as well. They provided their location as Guildford in the U.K., so it’s safe to assume that this raid test took place there as well.